KR0149852B1 - Method of making dibutyltinoxide containing catalyst pastes and use thereof - Google Patents

Abstract

A method of making a catalyst paste for electrocoating paints which can be cathodically deposited is provided, in which dibutyltin oxide is first predispersed with organic solvent and an organic acid customary for the neutralisation of electrocoating paints which can be cathodically deposited and is then dispersed and ground using the grinding binder and water.

Description

Method for producing catalyst paste containing dibutyltin oxide and uses thereof

The present invention relates to a method for producing a catalyst paste for cathodic separable electrophoretic deposition lacquers based on dibutyltin oxide (DBTO).

Cathodic electrophoretic immersion lacquer application is a known method of lacquer coating of electrically conductive cloth surfaces such as surfaces of metals, electrically conductive plastics, electrically conductive layers such as lacquers and the like. With this method, lacquer particles are deposited from the electrophoretic deposition lacquer bath onto the workpiece surface connected to the cathode. These solidified particles then develop to form a uniform smooth film, which can then be chemically crosslinked. The development and crosslinking process is often facilitated by heating the substrate.

In many applications, for example in the automotive industry, obtaining a particularly good appearance is essential for coatings. Thus, the coating must have a homogeneous and uniform appearance at various different surface properties and must be laminated uniformly. Likewise, it is not permissible to see scratches on the surface, such as ohmic pits, pin grooves or agglomerates. These are likely due to the dispersion of the binder or pigment used.

Grooves by binders, such as gel particles, for example, can occur when there is a non-uniformity in the synthesis of the resin, which can lead to different molecules and resin structures that affect gel formation. This may also occur after the synthesis of the binder, when extremely high temperatures are used in further processing to produce the electrophoretic immersion lacquer coating medium. This can lead to decomposition. Crosslinking reactions may also occur early. Such gel particles can cause surface scratches on the coated lacquer. They must therefore be removed by filtration or the specific temperature range should not be exceeded in the production and processing of the binder.

Pigment dispersion, ie dispersion of insoluble components such as pigments, catalysts, etc., generally occurs in the binder and frequently occurs in special paste binders. This paste binder may contain any ionic groups or groups that are ionizable by neutralization with a suitable acid. The pigment is added to the paste binder mixture with stirring, together with acid, solvent, optional deionized water and other additives. After adjusting to an appropriate viscosity, the obtained paste is ground into granules of a desired particle size. In this process, good dispersion is a prerequisite for proper retention time in the grinding unit. The grinding unit may for example be a bead mill. Dispersion of this viscous paste results in a significant amount of heat.

This heat must be removed by cooling from the paste during grinding because otherwise the paste may be irreversibly deformed. Therefore, it is necessary to pass the paste repeatedly through the grinding apparatus in order to improve the dispersion. This is expensive and expensive and can adversely affect the paste.

Different pigments, which are thought to contain other insoluble ingredients, such as solid catalysts, have different dispersion properties. In this respect, dibutylvin oxide, a commonly used delivery catalyst, is particularly difficult to disperse. Although poorly dispersed catalysts still catalyze in electrophoretic deposition baths, the film surface obtained is usually unacceptable. These surfaces contain pinholes or grooves and must be comminuted and processed before the next surface coating.

EP-B-O 193 685 discloses a DBTO paste in which DBTO is dispersed in a paysheet resin. To prepare this paste, the paste binder, dibutyltin oxide and completely deionized water are mixed and the mixture is ground in a suitable mill. The document makes no mention of grinding strength or the number of grinding passes. This DBTO paste can be used in electrophoretic immersion lacquer coating media and separated with the resin. In EP-A 0 251 772, conventional wetting agents are added to a mixture of paste resin, complete deionized water and DBTO. This paste must then be ground. In order to obtain a paste that can be easily dispersed in the coating medium, it must be ground for a long time under accurate temperature control.

One object of the present invention is to provide a paste containing a dibutyltin oxide catalyst which can be prepared in a simple manner which allows for a flawless coating during cathodic electro deposition without the need for long time grinding and thus no corresponding temperature problems. It is.

This object can be achieved by the present invention for producing a catalyst paste for cathodic separable electrophoretic deposition lacquer based on dibutyltin oxide, by grinding dibutyltin oxide together with a paste binder in the presence of water, the method Prior to milling, organic acids commonly used to neutralize dibutyltin oxide in organic solvents and cathodic separable electrophoretic deposition lacquers at a moisture content of up to 5% by weight relative to the total amount of dibutyltin oxide, solvent, acid and water It is characterized in that it is predispersed together with, and then pulverized by dispersing with a paste binder and water.

Surprisingly, it has been found that by preconditioning in a solvent and some of the acids present in the electrophoretic deposition bath, the powdery dibutyltin oxide is much better dispersed, allowing for a smooth and smooth electrophoretic deposition lacquer coating without scratches.

At the same time, the paste binder is not much sensitive to thermal stress. Moreover, production of pigment pastes is advantageous in terms of time and energy.

According to the process of the invention, the solid powdered dibutyltin oxide is first dispersed in an organic solvent. The particle size dispersion of the dibutyltin oxide powder may be equivalent to that of conventional catalyst powders for electrophoretic deposition lacquers or may be slightly higher as the grinding of the process of the invention takes place. Suitable particle sizes are, for example, less than 300 μm,

Suitable solvents for predispersion are those containing organic solvents, preferably OH and / or SH groups. Other functional groups, such as NH groups, may be present. Preference is given to solvents having OH groups.

Suitable solvents for this purpose are, for example;

(1) the boiling point is 50-300 ° C., preferably 90-250 ° C.

(2) the molecular weight is 32-450, preferably 32-300

(3) is at least partially miscible with the paste binder which prevents the finished pigment paste from separating,

(4) Under applicable conditions, that is, it can be obtained in the liquid phase during dispersion.

Examples of such solvents are OH such as methanol, ethanol, hexanol, cyclo hexanol, isobutanol, 2-ethyl-hexanol, C1-C11 alkyl phenol, ethyl glycol, butyl glycol, butyl diglycol, glycerin or hydroxyacetone And aliphatic or aromatic alcohols having one or more groups. Amino alcohols such as large methylaminopropane, dibutylaminobutane or cyclohexylaminobutanol are also suitable. Other suitable solvents include, for example, ethoxyethanol, epsipropane, hexoxypropane, hexoxybutane, hydroxyethyl acetate, hydroxybutyl acetate, di (hydroxypropyl) -malon ether or hydroxypropyl-acet OH-containing ethers, esters or amides such as amides. Mixtures of these solvents are also suitable.

Suitable for example are thiophenols, thiopropanes and cognate compounds containing other heteroatoms such as aliphatic or aromatic thiols, such as propane dithiol. These solvents may be used in combination as long as they do not react with each other or with each other.

Other non-reactive solvents may also be added to the solvent.

Examples include straight chain or branched aliphatic or aromatic hydrocarbons such as toluene, xylene, cyclohexane, n-hexane or isodecane. Ketones or esters such as methyl isopropyl ketone, diisobutyl ketone, cyclohexanone, butyl acetate, acetophenone, acetoacetic ester, isopropyl propionate, t-butyl acetate or 2-ethylhexyl butyrate may also be used. In addition, any ether such as diisobutyl ether, methyl isobutyl ether or di-t-butyl-diethylene glycol ether is suitable.

OH group-containing solvents are preferred and ethylene and / or propylene glycol or propylene glycol monoethers having a molecular weight of 50-200 g / mol are particularly preferred.

Such solvents may be added to the electrophoretic deposition bath to modify their properties in a conventional manner.

In preliminary dispersion, an organic acid is added to the solvent.

This is the acid commonly used to neutralize negatively separable binders in electrophoretic deposition lacquers in which the dibutyltin oxide paste of the present invention is added as a catalyst. This may be the same acid as the acid used following the binder or may be another acid.

This organic acid is a common acid used to neutralize electrophoretic deposition lacquers. They are preferably monobasic acids such as formic acid, acetic acid, lactic acid, dibutyl-phosphoric acid, octanoic acid.

The proportion of acid used for the preliminary dispersion is, for example, 0.05-5 molar acid per mole of DBTO used.

The acid is actually added anhydrously. This means that the water content of the entire mixture of acid, solvent, DBTO, water and any humectant predispersed is up to 5% by weight, preferably up to 2% by weight. It is preferable that a lower limit is 0.5 weight%.

In general, acids are advantageous if they are dissolved in a solvent and are present in the solvent in their dissolved state, but are not essential.

If desired, additives such as antifoaming agents or wetting agents such as 2,4,7,9-tetra methyl-5-decine-4,7-diol can be added to the mixture to be predispersed. In general, the total amount of such additives, in particular the total amount of humectant, is 3% by weight or less based on the total mixture.

When the DBTO is predispersed in a solvent or solvent mixture, an acid and possibly a humectant, the amount of solvent is low enough to stir in a stirrer such as a quick-acting stirrer (dissolver) at which a suitable viscosity is obtained. It is chosen to the extent that a liquid substance of viscosity can be provided. On the other hand, its viscosity should not be too low so that the dispersed particles can easily settle again. In order to obtain a suitable viscosity, the weight ratio between DBTO and the solvent is 4: 1 to 1: 4. If the mixture is too thin, the amount of DBTO must be increased to obtain good stability.

If the viscosity is too high, solvent must be added for proper dispersion.

Preliminary dispersion is carried out by a stirrer such as a rapid stirrer (such as a dissolver).

Dispersion time and temperature vary depending on the viscosity, type of acid and solvent, and type of stirring device.

Generally, the stirring time is 0.5-5 hours, preferably 1 to 3 hours. The temperature is controlled so as not to be heated to exceed the boiling point of the solvent used, and is generally heated above 110 ° C. This can be achieved by suitable cooling or heating. Theoretically, if the temperature is below the boiling point of the solvent, it is possible to work at any temperature, but at least a slightly elevated temperature, such as 40 ° C. or more, is suitable if one wants to obtain an advantageous dispersion time. Preferably the range is 50-80 ° C.

After preliminary dispersion, the resulting dispersion is further dispersed and ground after addition of the paste binder and water.

It is advantageous to add the paste binder and water directly to the dispersion, immediately without preliminary dispersion. The paste binder may be added first, water later, or a mixture of paste binder and water may be added.

The paste binder is added at a pumpable viscosity. For this purpose, it can be mixed with a solvent. Both solvents commonly used for electrophoretic deposition lacquers and predispersion are suitable for use as solvents.

Paste binders suitable for preparing DBTO pastes are binders commonly used for this purpose. These are known as paste resins. However, they may also be such binders which are used in electrophoretic immersion lacquers to form coatings and hereinafter referred to as binders for electrophoretic immersion lacquer coating media. In general, they are characterized by good water solubility and good wet content. Examples of such paste binders are described, for example, in EP-A 0 183 -025 or EP-A-270 877. These are resins which are dispersible in water, for example quaternary ammonium groups, or which are dispersed in water after being neutralized with an acid.

In the latter case, the amount of acid used for the preliminary dispersion is chosen to be suitable for dispersing the resin.

Water is added completely in the form of deionized water.

Paste binder and water are added while crossing the dispersion.

The amount depends on the viscosity required for grinding. In general, the weight ratio (based on solids) between DBTO and paste binder is from 1: 4 to 4: 1, preferably from 1: 2 to 2: 1. The amount of water is generally at least as much as the amount of the binder. The upper limit depends on the desired viscosity of the paste.

The homogenized mixture is then ground in a convenient manner in a mill such as a multi-compartment mill. Favorable dwell times for this process can be determined by the expert after several tests.

This depends on the flow rate, the size of the compartment, the drop in temperature and the amount and type of crushed material. This process provides a homogeneous, single pigment paste. When stored in the desired free flow form, this face is stable and does not settle even after long periods of storage.

By adding further paste binders, neutralizing agents, wetting agents, wheat pigments possibly to the catalyst paste thus made, it is possible to make colored pigment pastes. The latter is then ground into granules of the desired particle size in a suitable grinding device such as a bead mill. From the resulting pigment paste, after dilution with complete deionized water, the electrophoretic dip lacquer coating medium can be produced as a bicomponent material with a dispersion of binder or as a monocomponent material mixed with the desired lacquer binder.

This electrophoretic immersion lacquer coating medium is then used to coat the conductive material and then crosslinked with the lacquer film according to conventional methods. Of course, pigments may not be used. In this case, a clean electrospray coating is obtained.

Suitable pigments for addition to the pigment paste can be for example commercially available pigments. For example, titanium dioxide, carbon black, organic colored pigments, interference pigments, aluminum silicates, barium sulfate, lead chromium, lead carbonate or phyllosilicates can be used.

Another possibility is to add the catalyst paste produced according to the invention to the electrophoretic immersion lacquer coating material without further grinding. Even in this case, a smooth and flawless surface can be obtained as deposited on the baked cathode deposition-lacquer coated film.

Binders or binder mixtures that can be used with the electrophoretic deposition lacquer medium are conventional basic film-shaped resins or resin mixtures or crosslinkers. Examples of suitable resins are described, for example, in EP-A 0 261 385. These are resins that can be produced by radical polymerization of monomers containing olefin groups. These may contain OH, SH or amino groups or other functional groups, if desired. Examples of N-containing unsaturated monomers are N-dialkyl- or N-monoalkyl-aminoalkyl (meth) -acrylates, N-dialkyl- or N-monoalkylaminoalkyl- (meth) -acrylamides and / or And heterocyclic compounds having at least one basic nitrogen atom containing a vinyl group, such as N-vinyl-imidazole.

Polymerizable monomers containing OH groups are, for example, hydroxyalkyl (meth) acrylates or acrylamides. Other polymerizable compounds include, for example, allyl alcohol, monovinyl ethers of polyalcohols, vinyl aromatics, (meth) acrylic esters, (meth) acrylonitrile and vinyl ethers of monoalcohols. These compounds can be processed into polymers in a known manner by solution or emulsion polymerization.

The binder used according to the invention may contain an ion substituent or a substituent which can be converted to an ionic group. For example primary, secondary or tertiary amino groups, quaternary ammonium substituents and tertiary sulfur substituents. If the binder does not include an ionic group or an ionizable group, it is not a water-dispersible binder and can only be used in combination with other water-dispersible binders.

Suitable functional groups can be introduced directly into the binder via the monomer, but a substituent having the necessary properties can also be introduced by a post-polymerization reaction. Likewise, crosslinkable groups such as semi-blockde isocyanates can also be introduced in this way.

The solubility of the binder can be influenced by the number of amino or OH groups. Likewise, at least two reactive groups such as OH groups, reactive amino groups, reactive SH groups or blocked isocyanates are required for good crosslinking in the film.

The number must be controlled through the amount of the corresponding monomer in the reaction. The binder preferably has a molecular weight of 1500 to 30000, preferably 2500 to 20000.

Other suitable binders are disclosed in EP-A 0 082 291, DE-OS 26 15 810 or EP-A 0 234 395. These are basic base resins, their amine number is 20 to 250 and the average molecular weight number is 300 to 10000. The following groups are caused by basic groups; -NH2, -HRH, -NR2, NR + 3, -SR + 2, -PR + 3 and nitrogen-based groups are preferred. Basic resins are, for example, amino-epoxy resins, which are produced with the aid of known primary, secondary or tertiary amines. The chemical structure and properties of amino-epoxy resins can be greatly affected. Its properties can be influenced in the desired manner by appropriately selecting the epoxy resins and amines used, by changing the amount of functional OH groups, by changing the molecular weight and by adjusting the ratios between the soft or hard molecular moieties. Base resins include, for example, amino-epoxy resins with primary or secondary OH groups, amino-polyurethane resins and bisphenol A, Mannich bases based on reactive amines and formaldehyde, aminoepoxy resins with terminal double bonds and dihydroxy And conversion products of cyclic carbonates and amines based on cdidivinyl metal (bisphenol F) and dihydroxydivinyl propane (bisphenol A).

The base resin may self-crosslink or crosslink during external reagent treatment. Suitable crosslinkers are, for example, blocked polyisocyanates, melamine resins, crosslinkers capable of re-esterification and re-amidation. These crosslinkers are, for example, cross-linkers based on triazines in DE-A16 69 593, crosslinkers based on isocyanates masked in Farbe und Lack 1989 of the twelfth year issue of 1983, page 28 ff and EP-A 0 004 090 or DE A re-esterified or re-amidable crosslinking agent in -A 34 36 345 is described. The crosslinking agents may be added alone or in combination. Preferred binders or mixtures containing blocked isocyanates are: for example amino-epoxy resins, wherein the crosslinking reaction takes place via blocked isocyanates.

These binders can be neutralized by conventional acids and transferred to the aqueous phase. The organic acid used in this process is preferably monobasic acid such as formic acid, acetic acid, lactic acid, dibutyl phosphoric acid and octanoic acid. Some of the diacids that can be used to neutralize the binder can be used during the predispersion to produce the catalyst paste according to the invention. By using the required amount of acid from the electrophoretic immersion lacquer application bath, unnecessary extra acid is not used in DBTO paste production.

In addition, additives such as plasticizers can be added to the electrophoretic deposition bath in a suitable manner to improve the surface. Examples of caustic agents include phthalates, polyvinyl ethers or polyalkylene oxides or ethers thereof. If desired, low molecular weight non-neutralizable resins may be added in small portions to affect the properties of the film.

Electrophoretic immersion lacquer coating media are monocomponent or bicomponent materials. That is, electrophoretic deposition baths are made from a single component by dilution or from diluting a mixture of binder dispersions and pigment pastes in fixed proportions. The catalyst paste may be added to the deposition bath by pigment paste or to the electrophoretic deposition lacquer in later stages. It is homogenized quickly.

The amount of catalyst paste used depends on the catalysis of the resin binder mixture. This can easily be determined by experiment.

The electrophoretic deposition lacquer bath thus prepared makes it possible to coat the metal-conductive material in a known manner. Electrophoretic immersion lacquer coating deposits, at elevated temperatures, develop and perform crosslinking. The thickness of the dry film amounts to 10 to 50 mu m. The film may be further coated. Another method involves wet coating additionally on electrophoretic immersion lacquer films and baking them only when complete with this process. The secondary coating can be conventional fillers, top lacquers, metallic base lacquers and / or transparent lacquers. These may be solvent-containing, aqueous or binary systems. The resulting coating has a smooth, dense and uniform surface. They are, in particular, free from defects in horizontal planes such as scratches, pinholes, and small tangles.

The following examples illustrate the invention.

All percentages are by weight. Solid content is measured according to DIN 53 182 at 150 ° C.

Preparation of the binder:

Example 1

228 parts (lmol) of bisphenol A was dissolved in 42 parts of water produced by the reaction, and 260 parts (2 mol) of diethylaminoflophylamine and 66 parts of paraporium aldehyde in the presence of 131 parts of toluene by an azeotropic entrainer. React with (91%; 2mol).

After addition of 152 parts of diethylene glycol dimethyl ether and cooling the product to 30 ° C., 608 parts (2 mol) of toluylene-diisocyanate half blocked by 2-ethylhexanol are added over 45 minutes. When the NCO value actually reaches zero, 1400 parts of solution is 389 parts of diethylene glycol dimethyl ether, 190 parts of bisphenol A based epoxy resin (epoxy equivalent weight of about 190) and glycidyl ester of saturated tertiary C-C monocarboxylic acid 250 It is mixed with 1 part of a solution and reacted at 95-100 degreeC so that an epoxy value may become zero. Following addition of 40 millimoles of formic acid per 100 g of solid resin, the product should be diluted with water in a defect free manner.

Example 2

According to EP-B12 463. Diethanolamine, 391 g, 189 g of 3- (N, N-dimethylamino) propylamine, and hexane

1147 g of an additive of 2 mol of 1,6-diamine and 4 mol of glycidyl ester of versatic acid are added to 5273 g of bisphenol A ethoxy resin (epoxy equivalent weight of about 475) at 3000 g of ethoxypropane. The reaction mixture is kept at 85-90 ° C. for 4 hours and then at 120 ° C. for 1 hour with stirring. This is then diluted with ethoxypropanol to 60% solids.

Example 3

160 g of caprolactam is slowly added to 431 g (75% in ethyl acetate) of a reaction product solution of 3 mol of toluylene diisocyanate and 1 mol of trimethylolpropane at 70 ° C with stirring. The reaction mixture is then held at 70 ° C. until the NCO content is actually reduced to zero. 2-butoxyentanol (204 g) is then added and the ethyl acetate is distilled through the column at 70% solids.

Preparation of Pigment Paste:

Example 4

Ethoxypropane was mixed with 30 g, 2,4,7,9-tetramethyl-5-decine-4-7-diol wetting agent, 3.0 g of formic acid (50%) and 40 g of dibutyltin oxide in a dissolver and Disperse at 50-60 ° C. for about 2 hours.

Then 41 g (80%) of the paste resin according to EP-A 0 183 025, Example 5, followed by 73 g of complete deionized water are added thereto with stirring. This mixture is then ground in a suitable mill in two grinding passes to the required fineness. As a result, a liquid, viscous hazy pigment paste is obtained.

Comparative Test A

The following materials are successively added in a rapid stirrer and mixed:

37.5 g of ethoxypropane, 3.8 g of 2,4,7,9-tetramethyl-5-decine-4,7-diol wetting agent, 3.8 g of formic acid (50%), EP-A-183 025, Example 5 51.5 g (80%) of the binder, 50 g of dibutyltin oxide and 103.5 g of complete deionized water are stirred until homogeneous and then ground in a 6-8 grinding pass in a suitable mill to the required fineness.

Example 5

30 g of ethoxypropanol, 3 g of wetting agent, 2 g of acetic acid (100%) and 40 g of dibutyltin oxide are mixed in a dissolver and dispersed at 50-60 ° C. for about 2 hours.

Then 60 g (55%) of the paste resin according to EP-A 0 183 025, Example 3 are then stirred in 64 g of complete deionized water. Following homogenization the mixture is ground to the required fines of the particles in a suitable mill in two grinding passes.

Example 6

70 g (80%) of the binder according to EP-A 0 183 025, Example 5 are mixed with 7 g of formic acid (50%) and 250 g of deionized water. To this transparent racker is added 82.5 g of the paste according to Example 4, followed by 408 g of titanium dioxide, 120 g of aluminum silicate and 13.5 g of carbon black. Approximately 90 g of water is added to adjust the paste to a suitable viscosity. The solids content of such pigment paste amounts to about 60%. This paste is then ground to the required fineness of the particles in the bead mill.

Comparative Test C

The procedure is the same as in Example 6, but 82.5 g of the paste according to Comparative Test A is used instead of 82.5 g of the paste according to Example 4. The rest is the same as the previous one.

[Comparative Test D]

The procedure is the same as in Example 6, but instead of paste 1, 82.5 g of paste according to Comparative Test B is used.

Example 7

378 g of the binder according to example 2, 7.5 g of acetic acid (100%) and the paste according to example 5 are mixed. While stirring, 6 g of carbon black and 559 g of titanium dioxide are added. To achieve a suitable viscosity, about 500 g of butyl glycol are used and the pigment paste is ground to a suitable particle size with the aid of a suitable mill.

Lacquer Example:

The mixture is produced from 300 g of the resin according to Example 2 and 700 g (based on solids content) according to Example 1. The mixture is distilled off the solvent greatly by distillation, mixed with 45 g of lactic acid (50%) and converted to a suspension containing about 43% solids at elevated temperature. After dilution to about 15% solids content as complete deionized water, 333 g of pigment paste according to Example 6 are added to 1166 g of this suspension. The result is a cathode deposition bath with about 20% solids. In such a CED bath, the steel sheet is coated and then crosslinked by heating. The surface of the coated substrate (dry film thickness 20-22 μm) looks smooth and even and does not show film defects (CED = cathode electroprecipitation)

[Comparative Test E]

The procedure is the same as in Example 8, but the same amount of paste according to Comparative Test C is added by the pigment paste.

The test material is used for coating in the same manner as already described in Example 8. The surface looks rough and shows surface defects.

[Comparative Test F]

The procedure is the same as in Example 8, but the pigment paste described in Comparative Test D is used. The test substance is used for coating in the same way as in other cases. The surface obtained is smooth and homogeneous.

Example 9

The binder according to Examples 2 and 3 is mixed in a solid content basis ratio of 3: 1 and with formic acid (50%) 3.7 per 100 g of solid material. 719 g of paste according to Example 7 are added to 655 g of this mixture and the mixture is vigorously homogenized and then adjusted to have methoxypropanol at about 55% solids.

A CED bath of about 17% solids is produced from this material by dilution with complete deionized water. Such lacquers can be coated on conventional substrates. The surface obtained is homogeneous, dense and free of surface defects.

Claims (6)

Prior to milling the dibutyltin oxide, it is added to the total amount of dibutyltin oxide, solvent, acid, water and any humectant, together with organic and organic solvents commonly used to neutralize the cathodic separable electrophoretic deposition lacquer and any humectant. Dibutyltin oxide is pre-dispersed with the paste binder in the presence of deionized water, characterized in that it is predispersed at a water content of 0.5 to 5% by weight and then dispersed and pulverized with the paste binder and water. A process for producing a catalyst paste for zero catalytically separable electrophoretic deposition lacquers. The method according to claim 1, wherein the organic solvent is selected from OH and / or SH group-containing solvents or used in combination with other solvents. Catalyst paste prepared according to the method of claim 1. An electrophoretic deposition lacquer composition comprising a catalyst paste prepared according to the method of claim 1. 5. The composition of claim 4, wherein the electrophoretic deposition lacquer composition further contains a binder or binder mixture containing blocked isocyanates. A method of applying a cathodic electrophoretic deposition lacquer of an electrically conductive material, characterized by using a paste catalyst based on dibutyltin oxide produced according to the method of claim 1 or 2 as a catalyst.